Process for hydrocarbon oil conversion



Oct. 25, 1932. J. DE L. sEGUY PROCESS FOR HYDROCARBON OIL CONVERSION Filed Jan. 27, 1927 Patented Oct. 25, 1932 res rar, nr oFFlcE JEAN DELATTRE SEGUY, F CHICAGO, ILLINOIS, ASSIGNOR v TO UNIVERSAL OIL PRODUCTS COMPANY, 0F CHICAGO, ILLINOES, ACORPORATION OF SOUTH DAKOTA PROCESS FOR HYDROCARBON OL CONVERSION Application filed January 27, 1927. Serial No. 163,880.

The present improvements relate more par ticularly to a process for converting hydrocarbon oils into commercial products.

The invention is particularly designed to secure maximum yields of lighter gravity products, by subjecting light oils, such as kerosene, kerosene distillates, naphthenes, light gas oil cuts and the like having gravities of, say 35o Baume or lighter, to heat treatment.

It is Well known that the cracking of light er gravity oils gives better results under high superatmospheric pressures. However, in

. processes involving the return of reflux condensate for retreatment, the higher the presm sure maintained on the oil and vapors during treatment the greater quantity of light ends will be formed in the reflux, which lat-- V ter may be undesirable, decreasing the capac- Zo ity and efficiency of the plant in which the process is being carried out.

The invention comprising the subject matter of the present application proposes to remedy this situation and obviate the undesirable Objections thereto.

As al feature of the present invention, a high superatmospheric pressure is maintained on the heating tube and reaction drum,

. which pressure is materially decreased do-Wn 3o to or above atmospheric pressure. on the va pors entering the dephlegmator. This Will permit a maximum quantity7 of the light fractions contained in the reflux condensate to exit from the top of the dephlegmator in the form of vapors to be condensed as distillate.

As another feature of the present invention, I propose to subject the reflux condensate collecting in a pool at the bottom of the del phlegmator to a. reboiling action by passing through said pool and out of contact therewith, a liquid n'iaintained at a higher temperature than the reflux condensate.

This liquid may comprise a portion of the reflux condensate Withdrawn from the pool collecting in the dephlegmator, which is diverted to a closed cyclic circulatory system including a heating tube, a pump, and a heat exchanger located in the bottom of the deplegmator Where the reflux condensate collects in a pool. The oil being circulated through the closed cyclic system, is heated to a temperature higher than the temperature of the reflux condensate in the pool, said temperature being relative of course, to that necessary to secure the desired amount of reboiling of the reflux.

The utility of the invention as Well as other objects, features and advantages will be more particularly apparent from the following description.

ln the drawing, the single ligure is a diagrammatic side elevational view with certain parts broken away for the sake of clearness, of the apparatus of the present invention.

Referring more in detail to the drawing, l des nates a charging stock inlet line communicaiing with a suitable source of supply, in which may be interposed the valve 2 and pump 3. All or a portion of the charging stock may he diverted through line 4, in Which may be interposed the valve 5, the line 4 introducing ,the charging stock directly into the upper end ofthe dephlegmator 6, or all or aportion of the charging stock may be diverted through the line 7, in which may be interposed a valve 8, or regulated portions of the charging stock may be simultaneously diverted through each of the lines 4 and 7. The oil passing` through the continuation of the line 7 in which is interposed the pump 7 is subjected to conversion temperature in the heating` tube 9, mounted in the furnace, designated diagrammatically at 10, which may be heated by means of burners illustrated at 1l. After being raised to a conversion temperature by being passed through the `heating tube 9, which is subiected to the hot gases of combustion, the oil is transferred through transfer line 12 in which may be interposed valve 13 discharging into an enlarged reaction drum 14 of a type now in Wide` commercial use. rihis reaction chamber 14 may comprise a metal drum vertically disposed, as indicated, and provided with suitable manhole openings to permit cleaning thereof, and With suitable insulation or lagging if it is externally heated. lt may or not be externally heated. In the chamber 14 vapors separate, passing through the vapor transfer line 15, in Which may be interposed the valve 16 discharging into dephlegmator 6. The vapors in their upper passage through the dephlegmator 6 are retarded by means of the usual bailes 17 and are subjected to the usual reflux condensing action, which condenses the insufficiently cracked vapors, which collect as reflux condensate in a pool inA the bottom of the dephlegmator 6. The vapors Which have been sufficiently cracked, or those remaining un-Y condensedv after passing through the dephlegmator may be Withdrawn through the line 18, in 'which may be interposed the valve 19, being condensed in condenser, illustrated diagrammaticallyat 20, and collected as liquid distillate in receiver, designatedv diagram# matically at 21. This receiver may be provided lvvith'the usual liquid draw off pipe 22,

in which may be interposed the valve 23, and

With gas relief pipe 24, in Which may be interposed the valve 25. The reflux condenl sate from the poolmay pass through the line 26,` in Which may be interposed the branch line 27` controlled by valve 28, from which all or regulated portions of the reflux condensate may be Withdrawn. When the valve 28 is partially or totally closed, portions of reflux condensate may pass through the continuation of the line 26, in which is inter-V posed the valve 29, Which line 26 merges with a continuation ofv line 7 beyond valve 8, the

L z" reflux condensate being passed through the chamber '14 may be Withdrawn through any of the lines 30,'controlled by valve 31.

' Describing nonT oneof the features of the kpresent invention, the oil passing through the heatingtubes 9 is raised to a conversion tempera'ture of, say 80G-900 F. and maintained under va high superatmospheric pressure, say above 600 lbs. tothe square inch, more or less. This pressure is maintained on both the tube -1 9 and reaction chamber 14. In thepassage of the'vaporsreleas'ed in the reaction chamber 14 through tline 15, the valve 16, which has a pressure reducing valve, is so set as to materially decrease this pressure down to,

. say 100-125 lbs.`to the square inch, permitting substantial portions of the vapors to traverse the dephlegmator Without being condensedl and collected as reflux condensate. These heavier ends Which do condense at this reduced pressure, are collected in a pool in the bottom of the dephlegmator. This pool of reflux condensate Will be found to contain varying quantities of loW boiling point range fractions, which are refractory to cracking requiring high temperature, and it is of advantage to strip the reflux condensate of these light fractions. To accomplish this and as a feature of the present invention, there is circulated through a closed cyclic circulatory system including the heat exchanger 32, line 38 controlled by valves 34 and in Which is interposed pump valve 35, heating tube 36, return line 37, a liquid Which is heated to a higher temperature than the pool of reflux condensate.y This liquid may comprise any one embodiment of the invention, regulated portions of reflux condensate which are diverted through the line 38, in which may be interposed valve 39, into line 40 and through branch 41 and lpump 42 into the line 33.V Or regulated portions of the raW oil may be utilized as this liquid, being diverted through line Y43, in Which is interposed valve 44, into branch 41. Instead of using the line 43, eitherrof the branches 45, controlled by the valves 46', may be utilized.

In initially filling the closed cyclic circulatory system described, enough oil, Whether it be reflux or charging stock or other liquid medium, isv charged to the system in order to fill the same, after Which only that amount Will ybe added as is necessary to compensate for any vapors Which may be released through thev outlet header of the heat exchanger 32. A vapor line 47, controlled by valve'48, is provided to permit these vapors to pass into the dephlegmator. The pump 42 is provided to boost the pressure from one circuit to the other and to pass oil from the cracking circuit to the closed reheating circuit. It is obvious Vthat the heating tube 36 may or may not be positioned` in the same furnace as vthe heating tube 9,Y the object being to subject the liquid being passed therethrough to a higher temperature, which, in the furnacel shown, Would be accomplished. The liquid passing throughthe closed circuit is preferably maintained under a high superatmospheric pressure'to prevent any substantial vaporization of the reheating medium.

At any time during the operation the amount of oil circulated through the heating circuit is maintained constant, and any loss due to formation of vapors released through vapor pipe 47 is made up, as heretofore descr1bed,by introducing more reflux condensate or charging stock. The oil passing through the heating tube 36 is heated to a temperature of, say S900-1000o F., more or less, and the liquid medium passing therethrough maintained at a superatmospheric pressure of, say 400-500 lbs. to the square inch, more or less.

In the foregoing I have specified temperatures and pressures. It is to be clearly understood that these temperatures and pressures are purely illustrative and that the temperatures and pressures may vary Widely, depending upon the conditions of operation, the

type of charging stock, the products desired, all of which are under the control of a skilled operator.

I claim as my invention:

l. A process of hydrocarbon oil conversion, comprising subjecting oil to cracking conditions of temperature and superatmospheric pressure to cause substantial vaporization, separating said vapors and subjecting same to reflux condensation, collecting a pool of said reflux condensate, subjecting the pool of reflux condensate to a reboiling action to release lighter fractions thereof by passing a liquid heated to a higher temperature than the pool of reflux condensate through said pool but out of direct contact therewith in a closed cycle, utilizing a portion of said reflux condensate as the liquid medium circulating through said closed cycle, releasing vapors from said cycle and adding regulated portions of reflux condensate from the pool to the body circulating through the closed cycle in quantity sufficient to compensate for said vapors released from said closed cycle, whereby the amount of liquid in said closed cycle is maintained constant.

2. A hydrocarbon oil cracking process which comprises subjecting the oil to cracking conditions of temperature and pressure and separating evolved vapors from unvaporzed oil, dephlegmating said vapors thereby forming reflux condensate, collecting said reflux condensate in a body, withdrawing a portion of the reflux condensate from said body, heating said portion to a temperature sufficient to vaporize lighter fractions contained in said body and then passing the same in indirect heat exchange relation with said body thereby effecting a reboiling therein, separating from said portion of the reflux condensate vapors evolved by the heating thereof, combining the last named vapors with the vapors being dephlegmated, and condensing the dephlegmated vapors.

3. A hydrocarbon oil cracking process which comprises subjecting the oil tocracking conditions of temperature and pressure and separating evolved vapors from unvaporized oil, dephlegmating said vapors thereby forming reflux condensate., collecting said reflux condensate in a body, continuously circulating an oil in a closed ring including a heating Zone and a Zone in heat exchange relation with said body, heating the circulating oil in said heating zone to a temperature suflicent to vaporize lighter fractions contained in said body when the circulating oil is passed through the zone of heat exchange, separating from the circulating oil vapors evolved by the heating thereof and combining the last mentioned vapors with the vapors undergoing dephlegmation.

Il. A hydrocarbon oil cracking process which comprises subjecting the oil to cracking conditions of temperature and pressure and separating evolved vapors from unvaporized oil, dephlegmating said vapors thereby forming reflux condensate, collecting said reflux condensate in a body, withdrawing a portion of the reflux condensate from said body, and continuously circulating the same in a closed ring including a heating Zone and a Zone in heat exchange relation with said body, heating the circulating portion of the reflux condensate in said heating zone to a temperature sufficient to effect reboiling in said body when passed through the Zone of heat exchange, separating from said circulating portion vapors evolved by the heating thereof and combining the last mentioned vapors with the vapors being dephlegmated.

JEAN DELATTRE SEGUY. 

